In orthopedic devices, textile and/or foam liners are typically attached to frame elements of the device by using hook and loop fastener systems. The liners are provided in part to protect the user from the frame elements which may be rigid or semi-rigid, whereas the liners provide a comfortable interface between the user and the frame element.
It is common practice to use adhesives, ultrasonic welding, or other means to attach pieces of hook material to the frame element, and the liner includes or incorporates hook engageable material or pieces (i.e., loop material) to attach to the hook material pieces on the frame element. It is often found, however, that the shear forces applied to the adhesives on the hook material pieces, coupled with the temperature fluctuations and humidity inherent with orthopedic devices, causes the hook material pieces to slide and migrate over a period of use. This causes problems for the user, as the liner now improperly covers the frame elements, and pressure points may emerge at the edges of the frame element.
The hook material pieces may likewise be used for engaging a strap loop which retains the orthopedic device on the anatomy of the user. Again, adhesive applied hook material pieces tend to migrate which displaces the location of the strap and may lead to a deterioration of the efficacy in securing the device on the user.
In the past, injection molded hook integrally molded onto the frame element has been used to prevent the hook elements sliding and coming lose from the frame element. This is done in such a manner that an insert for the hook elements is placed into an injection molding tool for the frame element and an integrally-formed field of hooks is created during molding or manufacturing of the frame element so the hook is molded directly into the plastic of the frame element. Obviously, this method eliminates the need for adhesively applying the aforementioned hook material pieces and reduces the step of later applying hook material pieces later in the fabrication of an orthopedic device.
While injection molding the hook elements directly onto frame element is effective, it suffers from the drawback that many orthopedic devices do not lend themselves to including integrally molded hook elements. Knee brace shells are commonly post formed onto a user's leg mold after the frame elements are formed by injection molding rendered in a flat configuration. Because the frame elements may be subsequently contoured after the frame element itself is formed, integrally molded hook elements may become damaged during the post-forming and customization process. Due to the inherent differences in shape of each user, the integrally molded hook elements may be at a less favorable location after the frame element has been formed. Known methods for integrally molding hook elements lack flexibility for later modification in location and limit the degree by which frame elements may be customized for an individual user.